/Engine/Plugins/FX/Niagara/Source/Niagara/Classes/NiagaraSimCache.h
Reads Niagara attributes by name from the cache frame and appends them into the relevant arrays. When reading using this method the attributes for a FVector would come out as AoS rather than SoA so each component is wrote one by one EmitterName - If left blank will return the system simulation attributes.
void ReadAttribute ( [TArray](API\Runtime\Core\Containers\TArray)< float > & OutFloats, [TArray](API\Runtime\Core\Containers\TArray)< [FFloat16](API\Runtime\Core\Math\FFloat16) > & OutHalfs, [TArray](API\Runtime\Core\Containers\TArray)< int32 > & OutInts, [FName](API\Runtime\Core\UObject\FName) AttributeName, [FName](API\Runtime\Core\UObject\FName) EmitterName, int FrameIndex ) const